Additively Manufactured Ceramic Core Layers for Casting Surface Finish
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Solution Overview
Problem
Additively manufactured ceramic cores exhibit high porosity and surface roughness due to particle lamination, leading to poor surface finish and mechanical properties, which affect the quality of metal castings.
Innovation Solution
A ceramic core structure with a central part, a first layer, and a second layer, where the average erosion rates of the first and second layers are specifically controlled, and the ceramic powders used have varying particle diameters to enhance strength, collapsibility, and surface smoothness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If additive manufacturing is used to manufacture ceramic core, then manufacturing time and cost are reduced, but surface roughness increases and manufacturing precision deteriorates
Solution Approach 1:
The patent applies local quality by creating a multi-layer structure where the inner layer uses ceramic powder with larger particle diameter for collapsibility, while the outer layer uses ceramic powder with smaller particle diameter for smooth surface finish. This allows different regions of the ceramic core to have different surface qualities tailored to their specific functional requirements.
Solution Approach 2:
The patent uses composite materials by combining ceramic powders with different particle diameters in a layered structure. The inner layer contains ceramic powder with larger particle diameter (5-20 μm) for collapsibility, while the outer layer contains ceramic powder with smaller particle diameter (3-10 μm) for surface smoothness, creating a composite structure that achieves multiple competing requirements simultaneously.
2Adaptability or versatility
If additive manufacturing is used to manufacture ceramic core, then manufacturing flexibility is improved, but mechanical strength deteriorates
Solution Approach 1:
The patent applies local quality by creating a multi-layer structure where the inner layer uses ceramic powder with larger particle diameter for collapsibility, while the outer layer uses ceramic powder with smaller particle diameter for smooth surface finish. This allows different regions of the ceramic core to have different surface qualities tailored to their specific functional requirements.
Solution Approach 2:
The patent uses composite materials by combining ceramic powders with different particle diameters in a layered structure. The inner layer contains ceramic powder with larger particle diameter (5-20 μm) for collapsibility, while the outer layer contains ceramic powder with smaller particle diameter (3-10 μm) for surface smoothness, creating a composite structure that achieves multiple competing requirements simultaneously.
3Reliability
If ceramic powder with larger particle diameter is used, then collapsibility is improved, but surface roughness increases
Solution Approach 1:
The patent applies local quality by creating a multi-layer structure where the inner layer uses ceramic powder with larger particle diameter for collapsibility, while the outer layer uses ceramic powder with smaller particle diameter for smooth surface finish. This allows different regions of the ceramic core to have different surface qualities tailored to their specific functional requirements.
Solution Approach 2:
The patent uses composite materials by combining ceramic powders with different particle diameters in a layered structure. The inner layer contains ceramic powder with larger particle diameter (5-20 μm) for collapsibility, while the outer layer contains ceramic powder with smaller particle diameter (3-10 μm) for surface smoothness, creating a composite structure that achieves multiple competing requirements simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed structure achieves a ceramic core with improved surface roughness and mechanical properties, ensuring a smooth metal casting surface and effective collapsibility during removal.
Implementation Method 1
a first layer covering at least a part of the central part, and a second layer formed on a surface layer of the first layer
Implementation Method 2
forming the first layer by immersing the central part in a ceramic sol including a second ceramic powder with an average particle diameter D2 smaller than that of the first ceramic powder
Implementation Method 3
forming the second layer on a surface layer of the first layer by immersing the additively manufactured fired body with the first layer formed thereon in a ceramic slurry including a third ceramic powder with an average particle diameter D3 smaller than that of the second ceramic powder
Data Source
AI summary
According to the present invention, an additively manufactured ceramic core having both strength and collapsibility, and meltability and moreover having surface roughness improved is provided. The additively manufactured ceramic core disclosed herein is an additively manufactured ceramic core to be used as a core when manufacturing a metal casting and includes a central part corresponding to an additively manufactured fired body of a predetermined ceramic powder, a first layer covering at least a part of the central part, and a second layer formed on a surface layer of the first layer. When an average erosion rate corresponding to an average value of erosion rates calculated from an expression: erosion rate (μm/g)=B/A in which A g represents a projection quantity of projection particles and B μm represents an erosion depth in a fragility test is used, the average erosion rate of the first layer is lower than that of the central part and the average erosion rate of the second layer is higher than that of the first layer. The second layer has a surface roughness Ra of 10 μm or less.